title: Natural history of testicular regression syndrome and consequences for clinical management.
abstract: OBJECTIVE
  Testicular regression syndrome (TRS or 'vanishing testis') is a condition in which a testis is thought to have once existed but has atrophied and disappeared during early development. The natural history of TRS is in completely understood, due to the absence of any prospectively studied cohort of patients. This study aimed to quantify the cardinal features of the disease and correlate these with age.
  
  
  METHODS
  A total of 117 cases of TRS were submitted for histopathological examination. Patient age ranged from birth to 12 years, with a median age of 2 years. The proportion of each histological feature present was analysed according to age, using the chi(2) test. BIRTH RESULTS: The 117 cases accounted for 21% of the testicular/paratesticular specimens examined. Only 12 cases (10%) were found to contain testicular tissue, with no readily identifiable germ cells and in particular no atypical germ cells identified. Features such as haemosiderin-laden macrophages, calcification, the presence of a nodule, vas or epididymis were less prevalent amongst specimens from older boys.
  
  
  CONCLUSIONS
  This is the largest series studied to date. With only 10% of the removed specimens containing identifiable testicular tissue with no germ cells seen, a negligible risk of future germ-cell cancer on the affected side is implied. If the laparoscopic findings suggest a diagnosis of vanishing testis, we contend that a groin exploration may be no longer indicated.
authors.affiliation: Department of Paediatric Histopathology, Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Hegarty
authors.forename: Imran
authors.initials: I
authors.lastname: Mushtaq
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Sebire